ValarDragon Proposes Late-January 2027 Zcash NU8 Changes

ValarDragon has proposed a set of protocol changes for Zcash’s NU8 upgrade envisioned for late January 2027, including a fourfold increase in the block-size limit and new privacy features.

The proposal would raise the maximum block size from 2 MB to 8 MB. It also calls for a Tachyon shielded pool and an extensible transaction format intended to avoid adding distinguishability for hardware wallets that have not upgraded.

ValarDragon projects that combining Tachyon with larger blocks would enable about 200 shielded transactions per second. The ideas also include work on post-quantum privacy and transparent opcodes with SPHINCs variants at 128-bit and 192-bit security levels.

ValarDragon proposes moving the NSM redistribution date to around the seventh halving, saying the shift could delay the tail-emissions problem by one or two additional halvings. Another proposed change would set a date to stop Sapling deposits while keeping Sapling transactions and withdrawals enabled.

The proposal would also remove consensus branch ID updates. ValarDragon says those updates cause wallets to break during network upgrades. The post presents these as proposals for NU8, not as an approved upgrade plan.